1. Field of the Invention
The present invention relates to subject matter contained in Japanese Patent Application No. 7-216837 (filed on Aug. 25, 1995) and Japanese Patent Application No. 8-49967 (filed on Mar. 7, 1996). which are expressly incorporated herein by reference in their entireties.
The present invention relates to a portable endoscope in which a unit for supplying illuminating light to a light guide is attached to an endoscope control part.
2. Description of the Prior Art
A conventional portable endoscope has a light-emitting device for illumination which is provided in an endoscope control part. Such a conventional portable endoscope is generally arranged such that an entrance end portion of a light guide for transmitting light for illuminating an object is disposed in the endoscope control part, and an illuminating light supply unit is attached to the control part. The illuminating light supply unit contains a light source lamp for supplying illuminating light to the light guide and a power supply for the lamp, e.g. a dry battery.
Many of such conventional portable endoscopes adopt a structure in which the illuminating light supply unit is adapted to be detachable with respect to the endoscope control part, and a connecting cylinder for connecting the illuminating light supply unit projects from the control part.
Consequently, the connecting cylinder is heated by heat radiated from the light source lamp disposed in the distal end portion of the illuminating light supply unit, and this may cause the operator to feel uncomfortable when touching the heated connecting cylinder. Thus, the heated connecting cylinder may interfere with an endoscopic operation.
In many cases, the illuminating light supply unit of such a portable endoscope is formed into a hermetic structure from the necessity of washing, disinfection, etc.
However, if a gas is generated from the battery on account of some trouble occurring in the battery due to inappropriate management, the gas pressure in the illuminating light supply unit rises abnormally, giving rise to problems: a weak portion of the outer wall may be broken; and a cap and associated members which are removed from the unit on lamp replacement or battery replacement may be blown away by the high pressure in the unit at the instant of being disengaged from the unit.